DCT
5:25-cv-00194
Monroe Truck Equipment Inc v. Super Lawn Truck Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Monroe Truck Equipment, Inc. (Wisconsin)
- Defendant: Super Lawn Truck Inc. (Georgia)
- Plaintiff’s Counsel: Drew Eckl & Farnham, LLP; Quarles & Brady LLP
- Case Identification: 5:25-cv-00194, M.D. Ga., 05/13/2025
- Venue Allegations: Venue is alleged to be proper in the Middle District of Georgia because the Defendant has its principal place of business in the district and has allegedly committed acts of patent infringement there.
- Core Dispute: Plaintiff alleges that Defendant’s catalytic converter guards infringe a patent related to protective enclosures for vehicle exhaust components.
- Technical Context: The technology addresses the widespread problem of catalytic converter theft by creating a robust, frame-mounted physical barrier to prevent unauthorized access and removal.
- Key Procedural History: The complaint alleges that Defendant, a former customer of the Plaintiff, was sent a notice letter regarding the published patent application on July 18, 2023, and a second letter providing actual notice of the issued patent on January 9, 2025. These events form the basis of the willfulness allegations.
Case Timeline
| Date | Event |
|---|---|
| 2020-08 | Defendant purchases 70 catalytic converter guard kits from Plaintiff |
| 2021-08-30 | '695' Patent Priority Date |
| 2023-07-18 | Plaintiff sends notice letter to Defendant regarding published application |
| 2024-12-24 | '695 Patent Issue Date |
| 2025-01-09 | Plaintiff sends notice letter to Defendant regarding issued '695 Patent |
| 2025-05-13 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 12,172,695, “Catalytic Converter Guard,” issued December 24, 2024
The Invention Explained
- Problem Addressed: The patent identifies the problem of catalytic converters being forcibly removed from vehicles by thieves due to the value of the precious metals they contain and their typical location underneath the vehicle, which makes them "fairly easily accessible" (Compl. ¶10; ’695 Patent, col. 3:26-36).
- The Patented Solution: The invention is a protective guard that creates a physical enclosure around one or more catalytic converters. The guard is described as a box-like structure comprising a bottom plate, side mounting flanges that attach to a vehicle's frame rails, and front and rear "guard plates" that have cutouts to allow exhaust pipes to pass through, thereby shielding the converter from unauthorized access (Compl., Ex. A, Abstract; ’695 Patent, col. 5:24-41). This design allows it to be installed as an aftermarket add-on and to accommodate various vehicle and exhaust system configurations (’695 Patent, col. 3:40-43).
- Technical Importance: The patented approach provides a comprehensive enclosure that can protect multiple converters and is secured directly to the vehicle's structural frame, distinguishing it from simpler, single-converter clamps or cages that may offer less protection or require less secure mounting points (’695 Patent, col. 4:21-35, 45-50).
Key Claims at a Glance
- The complaint asserts infringement of "one or more claims" of the ’695 Patent (Compl. ¶22). Independent claim 1 is representative of the core invention.
- Independent Claim 1 requires:
- A set of mounting flanges
- An input guard plate
- An output guard plate
- A bottom plate extending between the flanges and plates
- The mounting flanges are configured to be secured to the outward-facing sides of a vehicle's frame rails
- The input guard plate is positioned adjacent to a converter's input and has a cutout for an input exhaust pipe
- The output guard plate is positioned adjacent to a converter's output and has a cutout for an output exhaust pipe
- The bottom plate extends beneath the converter
- The complaint does not preclude the assertion of other independent or dependent claims.
III. The Accused Instrumentality
Product Identification
- The accused products are Defendant’s catalytic converter guards, sold under the name "SLT Cat Cage" (Compl. ¶¶21, 25).
Functionality and Market Context
- The complaint alleges that after purchasing Plaintiff's guards, Defendant developed and began selling its own "knockoff" version (Compl. ¶21). The accused SLT Cat Cage is marketed to "Prevent theft of EXPENSIVE catalytic converters" and is sold online for specific vehicle models like "Isuzu and Chevrolet cab forward chassis trucks" (Compl. p. 6). A website screenshot provided in the complaint depicts the accused product as a perforated, multi-sided metal enclosure designed to be installed on a vehicle chassis (Compl. p. 6).
IV. Analysis of Infringement Allegations
The complaint references a claim chart in an exhibit that was not filed with the public document (Compl. ¶22). The following summary is based on the complaint's narrative allegations and visual evidence.
'695 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a set of mounting flanges; | The accused SLT Cat Cage is a structure alleged to have side components for mounting to a vehicle frame. | ¶22, ¶28 | col. 5:27 |
| an input guard plate; | The accused product is alleged to be an enclosure with a front-facing plate section. | ¶22, ¶28 | col. 5:28 |
| an output guard plate; | The accused product is alleged to be an enclosure with a rear-facing plate section. | ¶22, ¶28 | col. 5:28-29 |
| a bottom plate extending between the set of mounting flanges, the input guard plate, and the output guard plate; | The accused product is depicted as having a bottom surface that connects its side, front, and rear portions into a single enclosure. | ¶22, p. 6 | col. 5:29-32 |
| with the catalytic converter guard installed on the motor vehicle, the set of mounting flanges are secured to outward facing sides of each frame rail of a set of frame rails of the motor vehicle; | The complaint alleges the accused product is a guard for a vehicle, implying it is installed on the vehicle's frame rails in an infringing manner. | ¶22, ¶28 | col. 5:33-36 |
| the input guard plate is positioned adjacent an input of at least one catalytic converter and includes at least one cutout shaped to permit at least one input exhaust pipe to pass therethrough; | The complaint alleges the accused product fully embodies the invention, which requires a plate with a cutout for an input pipe. The product's purpose is to enclose a converter, which necessitates such a feature. | ¶22, ¶28 | col. 5:37-41 |
| the output guard plate is positioned adjacent an output of the at least one catalytic converter and includes at least one cutout shaped to permit at least one output exhaust pipe to pass therethrough; | The complaint alleges the accused product fully embodies the invention, which requires a plate with a cutout for an output pipe. | ¶22, ¶28 | col. 5:41-45 |
| the bottom plate extends beneath the at least one catalytic converter. | The product is depicted as a protective cage with a bottom wall intended to shield the converter from below. A website screenshot shows this feature (Compl. p. 6). | ¶22, p. 6 | col. 5:45-47 |
- Identified Points of Contention:
- Structural Questions: A key factual question will be whether the accused product, depicted in a website screenshot (Compl. p. 6), contains each of the claimed plates (mounting flanges, input/output plates, bottom plate) arranged in the specific spatial and functional relationship required by the claim. The complaint alleges the product is a "knockoff," suggesting a high degree of similarity, but proof of the exact structure will be necessary (Compl. ¶21).
- Scope Questions: The infringement analysis may turn on whether the accused product's mounting components meet the claim limitation requiring they be "secured to outward facing sides" of the frame rails. The complaint does not provide specific evidence of how the accused product is installed, raising the question of whether its installation method falls within the scope of this limitation.
V. Key Claim Terms for Construction
The Term: "a set of mounting flanges"
- Context and Importance: This term defines the primary interface between the guard and the vehicle. The claim requires a specific attachment location ("outward facing sides of each frame rail"). Infringement will depend on whether the accused product's attachment components and method meet this structural definition. Practitioners may focus on this term to determine if the accused product's design, which may use a different mounting strategy, falls outside the claim's scope.
- Intrinsic Evidence for a Broader Interpretation: The term "flange" is general. A party could argue it encompasses any projecting edge or rim used for attachment to the side of a frame rail.
- Intrinsic Evidence for a Narrower Interpretation: The specification and figures consistently depict the mounting flanges as the two primary side walls of the box-like structure, which include an offset portion to accommodate the frame rail and position the converter partially beneath it (’695 Patent, Fig. 1; col. 6:7-14). A party could argue the term should be construed to require this more specific structure.
The Term: "input guard plate" / "output guard plate"
- Context and Importance: These terms define the front and rear walls of the protective enclosure. Their identity is tied to their position relative to the converter and the presence of cutouts for exhaust pipes. The structural distinction between these "plates" and the "mounting flanges" is fundamental to the architecture of the claimed apparatus.
- Intrinsic Evidence for a Broader Interpretation: A party may argue that these terms refer to any front or rear surface of the guard that is adjacent to the converter and has a hole for a pipe to pass through.
- Intrinsic Evidence for a Narrower Interpretation: The specification describes these plates as elements that "extend between the first and second mounting flanges" (’695 Patent, col. 6:25-28). This suggests they are distinct structural components connecting the side flanges, not merely undifferentiated front and back sections of a single continuous piece.
VI. Other Allegations
- Indirect Infringement: The complaint does not contain a separate count for indirect infringement. However, the allegations may support such a claim. The complaint alleges Defendant sells products that directly infringe and provides visual evidence of "Installation Instructions" for its "SLT CAT CAGE™" (Compl. p. 7). This could form the basis for an induced infringement theory, which requires showing that Defendant actively encouraged or instructed its customers to install the product in an infringing manner.
- Willful Infringement: The complaint alleges willful infringement based on Defendant having received actual notice of its potential infringement. The allegations point to a letter sent on July 18, 2023, regarding the published application and another letter sent on January 9, 2025, regarding the issued ’695 Patent (Compl. ¶¶32-34).
VII. Analyst’s Conclusion: Key Questions for the Case
- A primary evidentiary question will be one of structural correspondence: does the accused "SLT Cat Cage," which the complaint calls a "knockoff," possess the specific multi-part structure recited in Claim 1—a bottom plate, two side mounting flanges, an input plate, and an output plate—and are these components installed on a vehicle's frame in the precise manner claimed?
- A central legal issue will be one of claim scope: can the term "set of mounting flanges", which are required to be secured to the "outward facing sides" of frame rails, be interpreted broadly to cover various attachment methods, or will its meaning be narrowed by the specific offset-wall structure shown in the patent's embodiments?
- A further question will concern willfulness and damages: given the allegation that Defendant is a former customer who received pre-suit notice letters, the court will have to determine if Defendant's conduct, if found to be infringing, was sufficiently egregious to warrant enhanced damages.